Portable Metrology Optimizes Olympic Skeleton Sleds

It is ironic that skeleton racing was born in Switzerland yet the speeds that the racers reach today as they hurtle down the track (up to 145 km/h) would actually qualify them for a heavy speeding fine on Switzerland’s motorways. “And not just that”, says Kristan Bromley, World, European and British Skeleton Champion and CEO of Bromley Technologies, “we are also subjected to forces of up to 5G as we go around corners. I wouldn’t want to do that on a motorway!”

Skeleton racing is a high-speed winter sliding sport. The athletes ride a small sled, lying face down and head first. While an early version of Skeleton originates on a Swiss track, built in the 1880s near to Davos and Klosters, Skeleton has become more and more popular in the intervening years and has been a permanent Olympic discipline since 2002.
Becoming Dr Ice However, Kristan Bromley’s path to world glory was as winding as an Alpine pass. Known as “Dr Ice” for the PhD degree he earned with a thesis about the performance of Skeleton sleds, Kristan originally trained to be a mechanical engineer.
His career started at British Aerospace, but as enthusiasm for Skeleton racing became outright speed on the track, within a year he had turned professional athlete and become British number 1. He was British champion for the first time in 1997, won his first world cup in 1999 and became European champion in 2004 and 2005, and World Champion in 2008.

In 2000, Kristan founded Bromley Technologies with his brother Richard, with the aim of building the fastest sleds in the world and promoting the sport to the wider public. Kristan, like Formula 1’s Bruce McLaren before him, now bids for glory on something that he developed. “I design it, Richard builds it then I test and race it”, he says.

For a sled to be fast down the track it must be energy efficient in every way. The sled has no active steering so the athlete uses shifts of his body weight and subtle body movements to steer left or right. Any sliding, skidding or unnecessary energy loss results in the loss of precious tenths of seconds. “To be honest you actually can’t see much when you’re cornering on a sled with your nose so close to the ground”, says Kristan Bromley. “The G forces are trying to push your head into the track, so you really need to feel that the sled is an extension of your body. However achieving that close relationship is extremely difficult because access to world-class tracks is so limited, so we now place huge importance on analysis and simulation. With Hexagon Metrology, we have found a partner that provides the perfect tool for help us do that.”
Scanning athletes and sleds Bromley Technologies now uses a ROMER Absolute Arm with integrated laser scanner as they seek to optimise their sled design. Using a touch probe and non-contact laser scanner, this high-precision portable metrology tool can digitise and measure a sled’s physical characteristics in minutes, making it perfect for a huge range of applications.

“The key is in understanding the factors governing the sled’s performance”, explains Kristan Bromley “The more we understand, the more effective our designs are and ultimately the faster the athlete and sled go. The ROMER Absolute Arm from Hexagon Metrology has been fundamental to this process. For example, using the arm’s laser scanner, we can scan an athlete’s body shape and generate accurate mesh data for CFD (Computational Fluid Dynamics) analysis in less than an hour.”

Furthermore, the curved underside of the sled (known as the ‘pan’) can also be scanned and compared to its original CAD model, to check for manufacturing defects.“But what’s even more useful is the fact that we can reverse engineer our pan from the scan data so as to adopt the best possible shape according to our CFD analysis.”

Kristan goes on: “The versatility of the arm made it perfect for our needs: we could immediately see where it would save us time in sled set up, but we’re now finding applications for it that we hadn’t even imagined before. Sled assembly, for example. We use the ROMER Absolute Arm’s touch probe to measure fixed ‘hard points’ on the sled so as to align the sleds components during assembly. This means that we can build with greater precision, and of course rest assured that we are building our sled to the required tolerances. Gaining performance is all in the detail.